Electrospinning is a process that can be used to form fibers, for example, polymer fibers or polyacrylonitrile (“PAN”) fibers. Electrospinning systems typically include at least one spinneret, which can include a needle or array of needles, a high voltage power supply, and a collector. The spinneret can also include a syringe in which a liquid solution (e.g., a polymer solution, particulate suspension, or particulate melt) is loaded. The high voltage power supply applies an electric field between the collector and the spinneret to extract the solution from the capillary. The electric field causes a droplet of the solution to become elongated at the tip of the needle or capillary, also known as the Taylor cone. When the force from the electric field exceeds the surface tension of the liquid, a jet of charged liquid is ejected from the capillary. The liquid dries in the air and the current flow migrates to the surface of the fiber. Electrostatic repulsion due to the charged surface of the fiber causes small bends or whipping that can elongate the fiber. The fiber is then collected on a collector that is grounded to dissipate the electric charge. In some circumstances, the fibers are heated after collection or submerged in a rinse bath (e.g., alcohol) to remove residual liquid and dry the fiber.
Conventional fiber tow manufacture, for example, is limited to fibers having a diameter of about 10 microns or larger. Electrospinning produces fibers that are typically less than 10 microns and can be as small as 10 nm. The fiber tows produced by an electrospinning process results in a yarn, e.g., tows with randomly oriented fibers.